Margin lending to leverage a rental property

[Clancy Catelli]

So heres the idea.... lol I want to build a duplex, but dont want to tie up a ton of cash in the process. I was thinking about borrowing $200k from my margin account threw Edward Jones @ 4.5 % (i think i have a year to pay it back, need to check) to build the the duplex myself. Once complete (6 months) I would rent each side for $1200, or $2400 total, use the income from the rental to refinance the duplex and pay off the margin loan. That way the $200k in my stock account is still still making around 9% a year (or $18,000), which pays for the intrest that im paying on the margin account. 

So basically im using borrowed money at +4.5%( actually making interest) to create around $1000 a month in cash flow, but wont cost me a dime to do. (Another great note is that a margin loan is not based off your income, its based of the account value, since its a secured loan. This could be the answer for people with alot of money but no W2 income for conventional lending. IS THIS POSSIBLE?